There have been known a hybrid vehicle on which an engine and an electric motor are mounted, or an electric vehicle including a travel distance extending function (range extender). In these vehicles, the engine and the electric motor are coupled by, for example, a planetary gear unit. The planetary gear unit and the electric motor constitute an electrical continuously variable transmission. Therefore, the engine rotation speed can be increased and decreased regardless of the vehicle speed. The engine rotation speed is generally controlled such that the thermal efficiency of the engine is optimized.
If the engine rotation speed is set regardless of the vehicle speed, a driver cannot manually select a ratio between the engine rotation speed and the rotation speed of an axle, i.e., a gear ratio. However, in the vehicle such as the hybrid vehicle as well, there is a demand to provide the driver with an operation experience of selecting the gear ratio, similarly to a general vehicle on which only an engine is mounted as a driving source. In order to respond to such a demand, in some hybrid vehicles, a pseudo gear ratio can be changed by increasing and decreasing the engine rotation speed in accordance with manual operation by the driver.
On the other hand, when the vehicle is configured such that the driver can select the gear ratio, an inappropriate gear ratio may be maintained. As one solution to this problem, Japanese Patent Laying-Open No. 2008-138827 (PTL 1) discloses giving, to the driver, a guide to the shifting operation in relation to the shift mode or gear when shifting to a shift gear by manual operation is determined as inappropriate.